The present invention relates to a main unit of a telephone system configured by connecting plural telephone control apparatuses together via dedicated lines, and also to a telephone control apparatus, and particularly to a main unit and a telephone control apparatus which have. a function of, when a holding operation is performed on a telephone set, requesting holding of a telephone control apparatus to which the remote telephone set belongs.
In a telephone system configured by connecting plural telephone control apparatuses together via dedicated lines, conventionally, when a telephone set which is communicated via one of the dedicated lines is to be held, a main unit to which a telephone set performing the holding operation belongs is held, another one of the dedicated. lines is seized, and a holding call is then transferred to a telephone set which belongs to another main unit set. Also after the transfer, therefore, two dedicated lines are occupied, and hence the resource of the dedicated lines cannot be effectively used.
A countermeasure against the above may be conducted in the following manner. When the holding operation is performed, a pulse signal is sent and received so that the telephone control apparatus to which the remote telephone set belongs is held, the transfer destination telephone set is called via a communication line, and the transfer operation is then performed. As a result, the dedicated lines are released, and the resource of the dedicated lines can be effectively used.
In the above-mentioned prior art in which holding is performed in a telephone control apparatus to which the remote telephone set belongs, when the holding operation is performed simultaneously in both communicating telephone sets, however, the pulse signals pass each other through the dedicated line, and both the telephone sets are held. As a result, the persons on both the telephone sides hear the holding tone, thereby producing a problem that the holding state cannot be cancelled.
The invention has been conducted in order to solve the problem of the prior art. It is an object of the invention to provide a main unit and a telephone control apparatus in which, even when the holding operation is performed simultaneously in both communicating telephone sets, both the telephone sets are prevented from entering the held state.
The main unit of the invention comprises: a channel switch which is connected to a remote telephone control apparatus via a dedicated line; and central controlling means for controlling the channel switch, and, when the central controlling means receives a hold request from a telephone set connected to the channel switch, the central controlling means sends out to the dedicated line a pulse signal requesting holding of the remote telephone control apparatus, and ignores for a constant time period a pulse signal which is sent from the remote telephone control apparatus via the dedicated line.
According to the invention, it is possible to obtain a main unit in which, even when the holding operation is performed simultaneously in both communicating telephone sets, both the telephone sets are prevented from entering the held state.
The main unit set of the invention comprises: a channel switch which is connected to a remote telephone control apparatus via a dedicated line; and central controlling means for controlling the channel switch, and, when the central controlling means receives a hold request from a telephone set connected to the channel switch, the central controlling means sends out to the dedicated line a pulse signal requesting holding of the remote telephone control apparatus, and ignores for a constant time period a pulse signal which is sent from the remote telephone control apparatus via the dedicated line. The main unit has a function of, even when two telephone sets connected together via a dedicated line simultaneously perform the holding operation and the pulse signals pass each other through the dedicated line, preventing both the telephone sets from entering the held state.
Preferably, if, when the central controlling means sends out the pulse signal to the remote telephone control apparatus, it is judged that holding of the remote telephone control apparatus is disabled, the central controlling means sets holding in an own side. The main unit has a function of, if holding of the telephone control apparatus to which the remote telephone set belongs cannot be performed, controlling the telephone control apparatus which is the source of the pulse signal, so as to automatically perform the holding operation.
Preferably, if it is judged that holding of the remote telephone control apparatus is disabled, the central controlling means connects a voice guidance device to the telephone set which produces the holding request. The main unit has a function of, if holding of the telephone control apparatus to which the remote telephone set belongs cannot be performed, notifying this situation to the person who has performed the holding operation.
Further, the telephone control apparatus of the invention comprises: a channel switch which is connected to a remote telephone control apparatus via a dedicated line; central controlling means for controlling the channel switch; a telephone set connected to the channel switch; and pulse signal sending means, connected to the channel switch, for, when the telephone set is held, sending out a pulse signal to the dedicated line to request holding of the remote telephone control apparatus, and, when the central controlling means receives a hold request from the telephone set, the central controlling means sends out the pulse signal, and ignores for a constant time period a pulse signal which is sent from the remote telephone control apparatus via the dedicated line. The telephone control apparatus has a function of, even when the holding operation is performed simultaneously in both telephone sets connected together via a dedicated line and the pulse signals pass each other through the dedicated line, preventing both the telephone sets from entering the held state.
Preferably, if, when the central controlling means sends out the pulse signal to the remote telephone control apparatus, it is judged that holding of the remote telephone control apparatus is disabled, the central controlling means sets holding in an own side. The telephone control apparatus has a function of, if holding of the telephone control apparatus to which the remote telephone set belongs cannot be performed, controlling the telephone control apparatus which is the source of the pulse signal, so as to automatically perform the holding operation.
Preferably, the telephone control apparatus set further comprises a voice guidance device which performs voice guidance, and, if it is judged that holding of the remote telephone control apparatus is disabled, the central controlling means connects the voice guidance device to the telephone set which produces the holding request. The telephone control apparatus has a function of, if holding of the telephone control apparatus to which the remote telephone set belongs cannot be performed, notifying this situation to the person who has performed the holding operation.